The present invention relates to a method and/or architecture for storing flags generally and, more particularly, to a programmable pin flag.
Information regarding semiconductor devices on a wafer such as test results, repair status, wafer location, and manufacture lot need to be available after the devices are assembled into integrated circuit packages. Devices without the information stored and readily accessible must be tested (or retested) after packaging to determine, for example, speed of operation or cause of failure. Information such as manufacturing lot or wafer location can not be determined after packaging. Conventional methods for storing device information on devices include (i) placing visible. markings on the device, (ii) adding memory cells and control circuitry for storing the information, and (iii) adding laser blown fuse circuits.
However, conventional approaches have one or more of the following disadvantages: (i) visible markings are destroyed or unreadable when the device is packaged, (ii) increased process expense and design complexity, (iii) added memory circuitry can require significant die area and overhead, and/or (iv) laser blown fuses require a laser as well as test circuitry on the test fixture.
It would be desirable to have an architecture and/or method for storing information at a device pin.
The present invention concerns an apparatus comprising a storage element coupled between a first and a second bond pad. The storage element having a physical characteristic that can be measured and altered. Data may be stored in the storage element by altering the physical characteristic.
The objects, features and advantages of the present invention include providing a programmable pin flag that may (i) be implemented with a simple wafer process, (ii) be implemented with a simple circuit, (iii) be programmed at sort and retrieved for class testing, (iv) share bond pads with standard circuitry, (v) have no effect on standard circuit operation, (vi) minimize program and retrieval times, (vii) allow easy data retrieval, (viii) use little die area, and/or (ix) have low fabrication cost.